As is well known in the art, typical internal combustion piston engines are highly inefficient during operation. For example, if you end a power cycle for a four cycle engine, the exhaust valve must be held open when its associated piston reaches bottom dead center. Various studies have estimated that such operation causes more than fifty percent of the power generated by the combustion of fuel in the engine to be lost. By providing a longer power cycle for each piston of the engine, it is theoretically possible to improve efficiency. However, because of the requirement of mechanical timing, and the requirement that exhaust and intake valves are typically mechanically opened and closed, the provision of longer power cycles is very limited, in that the distance a reciprocating piston travels between spark plug ignitions of the fuel/air mixture or between combustion cycles is substantially fixed, in turn, limiting gains in efficiency. Greater efficiencies can be obtained by employing a piston that rotates repetitively in a circle, thereby avoiding the reciprocal motion of the pistons in a typical internal combustion engine.
Rotary engines known in the art employ electronic controllers for controlling ignition and fuel injection. For example, in Warwick U.S. Pat. No. 4,078,529, entitled “Rotary Engine,” such electronic control is utilized. Also, ignition timing is controlled through use of magnets that rotate in unison with a rotary piston for generating an electric pulse in a stationary coil as they pass the coil, whereby the pulses are amplified and utilized for triggering an electronic or capacitor discharge ignition system. However, the rotating cylinder block of this engine employs a plurality of reciprocating pistons. As a result, inlet and outlet ports must be opened and a closed at appropriate times during operation of the engine. Also, fuel combustion occurs within the piston chamber. Accordingly, the length of the power stroke of a piston, that is the length of the power cycle cannot be adjusted or varied relative to load conditions.
Satou et al., U.S. Pat. No. 4,096,828, entitled “Rotary Piston Internal Combustion Engine,” teaches a Wankel type engine that employs a first combustion chamber for the initial combustion of fuel from which the partially combusted air/fuel mixture is passed into the piston chamber also serving as a second combustion chamber in which additional fuel is mixed with air and ignited during the combustion cycle. Air is provided to the engine through a first port, and spent combustion products are ejected from a second port. A similar arrangement is taught in Muroki et al., U.S. Pat. No. 3,976,036, entitled “Rotary Piston Engines.” Such engine configurations substantially fix the distance a piston travels during a power cycle.
In Stumpfig, U.S. Pat. No. 3,240,189, entitled “Rotary Piston Combustion Apparatus,” a rotary piston is provided in a number of embodiments that employs the use of regularly extending vanes or separating elements which are moveable toward the inside wall surfaces of the piston chamber case or housing. The vanes extend and retract regularly as the piston rotates. Air is drawn into one portion of the piston chamber from a single inlet port, and spent combustion products are exhausted from a single exhaust port as the piston is rotated. Fuel is ignited in an evaporation chamber via a spark plug, and the ignited fuel is passed into the piston chamber for further mixing with air for completing the combustion thereof. As indicated such an engine configuration provides a fixed distance for piston travel during a power cycle.